Split string in C every white space

For the fun of it here's an implementation based on the callback approach:

const char* find(const char* s,
                 const char* e,
                 int (*pred)(char))
{
    while( s != e && !pred(*s) ) ++s;
    return s;
}

void split_on_ws(const char* s,
                 const char* e,
                 void (*callback)(const char*, const char*))
{
    const char* p = s;
    while( s != e ) {
        s = find(s, e, isspace);
        callback(p, s);
        p = s = find(s, e, isnotspace);
    }
}

void handle_word(const char* s, const char* e)
{
    // handle the word that starts at s and ends at e
}

int main()
{
    split_on_ws(some_str, some_str + strlen(some_str), handle_word);
}

http://www.cplusplus.com/reference/clibrary/cstring/strtok/

Take a look at this, and use whitespace characters as the delimiter. If you need more hints let me know.

From the website:

char * strtok ( char * str, const char * delimiters );

On a first call, the function expects a C string as argument for str, whose first character is used as the starting location to scan for tokens. In subsequent calls, the function expects a null pointer and uses the position right after the end of last token as the new starting location for scanning.

Once the terminating null character of str is found in a call to strtok, all subsequent calls to this function (with a null pointer as the first argument) return a null pointer.

Parameters

  • str
    • C string to truncate.
    • Notice that this string is modified by being broken into smaller strings (tokens). Alternativelly [sic], a null pointer may be specified, in which case the function continues scanning where a previous successful call to the function ended.
  • delimiters
    • C string containing the delimiter characters.
    • These may vary from one call to another.

Return Value

A pointer to the last token found in string. A null pointer is returned if there are no tokens left to retrieve.

Example

/* strtok example */
#include <stdio.h>
#include <string.h>

int main ()
{
  char str[] ="- This, a sample string.";
  char * pch;
  printf ("Splitting string \"%s\" into tokens:\n",str);
  pch = strtok (str," ,.-");
  while (pch != NULL)
  {
    printf ("%s\n",pch);
    pch = strtok (NULL, " ,.-");
  }
  return 0;
}

Tags:

C